DE3201254A1 - SEWING MACHINE - Google Patents

Description

Nähm ash ine

The invention relates to a sewing machine according to the preamble of the main claim. 5

Such sewing machines are shown in DE-PS 454 145, 483 989 and 516 614, for example. In such sewing machines, which form a double chain stitch, it is problematic to have a flawless one Penetration of the needle tips into the through the needle evasive movement and the fabric feed formed thread triangle. This difficulty is particularly evident with short stitch lengths and multi-needle machines.

To address this deficiency, spreaders have been proposed, the needle and / or Looper thread in one direction for stabilization of the thread triangle. Enlarge all of these generic sewing machines provided with spreaders the thread triangle at the point that is essential for the penetration of the needle.

As a rule, it is necessary to let the needles pass the hook so closely that that they touch the gripper. This leads to a rapid wear and tear of the needles Damage to the sewing material due to needles damaged at the tips and undesired needle heating.

The invention is based on the object in a generic sewing machine To arrange and train spreader in such a way that these deficiencies are avoided. 5

The object is achieved by the measures described in the claims.

By arranging the movement path of the spreader according to the invention, the looper thread deflected in the area in which this is caused by the needle evasive movement and the material feed formed thread triangle is closest. The looper thread is deflected so far that it runs at a distance approximately parallel to the back of the hook. The resulting free space allows the needles to penetrate correctly with greater security Loop of the looper thread, the looper like this set that the needles pass the hook at a greater distance than usual. This prevents the needles from touching the gripper and all the detrimental effects that arise therefrom Consequences avoided. The spreader arrangement according to the invention also brings more loose looper thread in the seam, causing a contraction in multi-needle sewing machines the seam is safely avoided.

The subject of the invention is in the drawing for example shown.

Show it:

1 shows a section of a sewing machine

with the stitch formation area and the hook at the beginning of the take-up of the needle thread loop.

Fig. 2 the same. When the needles enter

into the gripper loop.

The sewing machine has a conventional oscillating needle bar 1 with needles attached to it 2, which together with a looper 3 for entangling the needle and looper thread 4, 5 serve. The gripper 3 is fixed in a holder 6, which in a known manner over Transmission means of a not shown Main shaft is driven. The sewing machine also has a knife valve 8, which is also driven by the main shaft. Furthermore is from the main shaftin Needle stop 9, which is attached to a holder 11, is driven.

According to the invention, this holder 11 also serves as a carrier for a spreader 12, which is transverse in the direction of fabric feed

moved over the gripper 3. To the distance between the throat plate, not shown and to keep the gripper 3 as small as possible, the gripper 3 instructs on its back Trough 13 through which the spreader 12 can pass when it moves in the direction of the looper thread 5.

The gripper 3 moves in the usual way transversely to the material feed direction to

of the needle thread 4 by the increase in

P needles 2 formed needle thread loops

step. The needle stop 9 moves at the same time against the direction of material advance up to to the needles 2, and the spreader 12 has moved away from the gripper 3 accordingly.

After the looper 3 loops the needle thread recorded and the needle evasive movement has run, he moves on the other

Side of the needle track backwards. The needle stop 9 moves away from the needle path at the same time In the direction of advance of the material, the spreader 12 follows this movement. Crossed it the spreader 12 moves the looper back through the trough 13 and grasps the looper thread 5.

While the looper 3 continues to move backwards, the spreader 12 urges the looper thread 5 further in the material feed direction. As a result, the looper thread 5 runs with a relatively large Distance approximately parallel to the gripper and allows the needles to be used when descending Distance to let the gripper pass that contact is avoided.

The drive of the spreader 12 can take place from

Needle stop 9 of course also from a separate drive, or the drive of another itself take place in the material feed direction moving part. The arrangement and movement of the spreader is equally effective, both for single-needle, as well as with multi-needle machines.

Claims (4)

UNION SPECIAL GmbH B 374 / ss Schwaabstrasse 33 December 28, 1981 Stuttgart 1 PATENT CLAIMS 1. Sewing machine with oscillating needles and a thread running across the fabric feed direction a movement to pick up the needle thread loops and in the sewing direction a needle evasive movement executing gripper, as well as a spreader for the Looper thread that grips the looper thread running from the looper eye to the last stitch and expands it in the direction of feed, before the needles pass the looper thread as they descend, characterized in that that the trajectory of the spreader (12) between the one closest to the gripper eye in the foremost gripper position lying needle track and the gripper eye runs. 2. Sewing machine according to claim 1, characterized in that the spreader (12) on one existing, in the material feed direction oscillating drive part (11) attached is. 3. Sewing machine according to one of the preceding claims, characterized in that the spreader (12) with the drive part (11) is connected to a needle stop (9). 4. Sewing machine according to one of the preceding claims, characterized in that the spreader web over the back of the hook runs and the looper back with a Trough (13) for the passage of the spreader (12) is provided.